Hinged stopper of plastics material

ABSTRACT

This stopper ( 1 ) comprises a capping lid ( 20 ) which, in the back portion of a tubular base ( 10 ) for surrounding a container neck, forms part of the upper end ( 10 A) of this base, forming a joint ( 30 ) with hinges ( 31 ) which defines a geometric axis (A-A) for pivoting the lid between the open and closed service positions. To limit the risk that a child, playing with the stopper, could remove the lid, while at the same time enabling the lid to be opened reliably and satisfactorily by the joint in relation to the base, the joint has two lines of least mechanical resistance ( 14 ), which extend from the upper end to the lower end ( 10 B) of the base, being positioned, at the level of said upper end, on both sides of the joint, and which are designed to break before the joint can tear completely when the lid, in open position thereof, is rotated on itself around a geometric axis transverse to the pivoting axis (A-A).

The present invention relates to a plastics material stopper for a container neck. The invention applies more particularly to so-called “hinged” stoppers, i.e. stoppers that include a cap that can be tilted relative to a base that is designed to surround the neck of the container in permanent manner, by deforming a hinge having one or more members connecting the base integrally with the cap. Examples of stoppers of this type are given in WO-A-03/006333 and WO-A-03/059770.

That type of stopper can raise safety problems with children: if a child is playing with the hinged stopper and subjects it to stresses other than the normal stress for tilting about its hinge member(s), such as stressing in twisting and/or in traction, the hinge member(s) might tear, thereby separating the cap from the base. The child then inhales the cap through the mouth and runs the risk of choking.

The object of the present invention is to propose a hinged plastics stopper that not only provides reliable and satisfying hinging between its cap and its base for opening and closing the stopper, but also limits any risk that a child might manage to tear off the cap when playing with the stopper. In particular, the invention seeks to provide a hinged plastics stopper that satisfies the French standard relating to child safety, referenced NF EN 71-1, or classified under the reference S 51-212, that makes provision for applying a twisting force and then a traction force on an article under test, and under certain test conditions.

To this end, the invention provides a stopper of plastics material for a neck of a container, the stopper comprising a generally tubular base for surrounding the neck and a closure cap that is formed in a peripheral portion of the base integrally with a first longitudinal end of the base, forming a hinge with one or more hinge members defining an axis for tilting the cap relative to the base between open and closed service positions, the stopper being characterized in that the base presents two elongate zones of weakness that extend lengthwise from the first end of the base towards the second longitudinal end thereof, being situated at said first end on either side of the hinge and adapted to break before the hinge can be torn through when the cap, in the open position, is turned over around a twist axis extending transversely to the tilt axis.

In order to guarantee safety of a child playing with a hinged stopper of the above-mentioned type, in particular in accordance with the above-specified French standard, such a stopper is required to present a cap that either presents a diameter greater than a predetermined value chosen to ensure that if the cap is torn from the base it cannot be inserted into a child's wind pipe, or else sufficient strength in its connection with the base to ensure that cannot be completely separated from the base when the connection zone is subjected to a predetermined level of twisting, or the cap is even twisted right over about a test axis perpendicular to the normal tilt axis of the cap between its open and closed position. The idea on which the invention is based is to guarantee that the cap of the stopper in accordance with the invention can be turned over, i.e. twisted about a twist axis, in particular under the conditions specified by the above-mentioned standard, without applying significant stresses to the hinge member(s), and thus ensuring that the hinge is not torn through even though it presents low breaking strength given its relative flexibility. If it is considered that the base of the stopper in accordance with the invention extends lengthwise in a vertical direction, with the cap on top, the base has two elongate zones of weakness on either side of the peripheral portion of its top end that is hinged to the cap, which zones of weakness extend from its top end towards its bottom end. When the cap is tested in bending, each of these two zones breaks almost immediately, i.e. before the hinge is subjected to significant levels of twisting stress. As a result, instead of concentrating at the high end of the base, i.e. at the hinge, twisting stresses are distributed over a portion of plastics material carrying the hinge and defined between the two zones of weakness, over the entire length of those zones. This greatly limits the risk of the material connection connecting the cap to the base being torn right through under the effect of excess local stresses when the connection is subjected to twisting, in particular with the cap being turned over while in its open position.

Thus, the safety of a child playing with a stopper in accordance with the invention, in particular a child twisting the cap relative to the base at its hinge, is improved whatever the maximum transverse dimension of the cap, in particular regardless of its diameter if the cap has a circular base. In other words, the invention can be applied to stoppers of plastics material having a wide variety of dimensions. In addition, unlike a solution to the above-posed problem that consists in increasing the strength of the hinge between the cap and the base, in particular by reinforcing the portions adjoining said hinge by ribs or extra thickness of plastics material, the zones of weakness in accordance with the invention are made by reducing the amount of plastics material that is used, thereby reducing the total weight of the stopper.

Furthermore, it can be understood that when the cap of the stopper in accordance with the invention is stressed in its normal conditions of service, i.e. when it is tilted between its open and closed positions relative to the base, the presence of two zones of weakness in accordance with the invention has no effect, i.e. these zones do not disturb normal titling of the cap and do not impose any limit on its mechanical performance relating to tilting. In particular, the two zones of weakness in accordance with the invention may be incorporated in a hinged stopper that presents the advantageous arrangements described in WO-A-03/006333. In other words, when two successive hinge members around the periphery of the base of the stopper in accordance with the invention are provided to constitute the hinge between the cap and the base, the cap is advantageously provided with a projection that is adapted to come to bear against a tongue formed by the first end of the base, between the two hinge members, to hold the cap in its open position with an opening angle of at least 180°.

In a preferred embodiment, the two zones of weakness are dimensioned and configured relative to the base in such a manner that, after breaking, they define between them a portion of base material that carries the hinge and that is adapted to work in twisting without breaking when the cap is turned over about the twist axis through at least 180°. As a result, the cap can be turned right over relative to the base without it being possible to separate it from the base, in particular by breaking the hinge, thereby satisfying the twist test of the above-specified standard.

With advantageous practical dimensions, each zone of weakness presents, in the longitudinal direction of the base, a dimension that is greater than one-fourth, and preferably greater than half the length of the base.

In a preferred arrangement, the two zones of weakness extend lengthwise converging towards each other on going away from the first end of the base. As a result, when the cap is turned over about the twist axis, a major fraction or even substantially all of the twisting stress on the material connection between the base and the cap is concentrated in the portion of material between the bottom ends of the two zones of weakness. In other words, the twisting stresses are taken up longitudinally in the main portion of the base at a good distance from the hinge member(s), thereby correspondingly preserving the structural integrity of said member(s).

With advantageous practical dimensions concerning the portion of material of the base that is defined by the two zones of weakness, between their ends remote from the first end of the base and in the peripheral portion of the base associated with the hinge:

-   -   said portion presents, in a plane perpendicular to the         longitudinal direction of the base, a section that is greater         than or equal to the section of the hinge member(s); and/or     -   said portion presents a thickness that is strictly greater than         the thickness of the hinge member(s).

To enable the cap of the stopper in accordance to withstand a traction force applied along the twist axis, in particular in the context of a traction test performed subsequent to the twist test as set out by the above-mentioned French standard, a longitudinal portion of the material of the base that extends between the longitudinal ends of at least one of the zones of weakness remote from the first end of the base, and the second end of the base presents a dimension in the longitudinal direction of the base that is greater than 10% of the length of the base. As a result, after the zones of weakness in accordance with the invention have performed their role of preserving the structural integrity of the hinge between the cap and the base, these zones are dimensioned relative to the base so as to limit any risk of the turned-over cap being torn off when pulled away from the base. Nevertheless, it can be understood that even when applying the traction force leads to the base tearing, by cracks propagating through the plastics material downwardly extending the zones of weakness to the bottom end of the base, the resulting torn-off stopper presents a transverse dimension that is very large, thus, in practice, preventing the stopper from being inhaled by a child.

In an arrangement that can be used as an alternative to or in conjunction with the above arrangement, for the purpose of improving retention of the structural integrity of the base when the cap is thus stressed in traction, at least one of the zones of weakness is extended at its longitudinal end remote from the first end of the base by an elongate opening formed in the base, said opening extending lengthwise from said zone of weakness in a direction that is substantially peripheral relative to the base and away from the other zone of weakness. As a result, cracks in the material started at the bottom ends of the zones of weakness in accordance with the invention are guided by said openings around the periphery of the base, i.e. in a direction allowing the tears to progress through a large amount of material before compromising the structural integrity of the base.

In a practical embodiment, each zone of weakness comprises firstly a through slot that extends lengthwise from the first end towards the second end of the base, and secondly at least one breakable element connecting together the longitudinal sides of the slot, and adapted to break before the hinge can be torn through when the cap in its open position is turned over about the twist axis. Advantageously, the breakable element(s) is/are disposed at the longitudinal end of the slot that is situated at the first end of the base.

In a possible embodiment, the two zones of weakness define between them a portion of material of the base that carries the hinge and that is provided, in its middle portion around the periphery of the base, with a through orifice of elongate shape in the longitudinal direction of the base. This through orifice makes it possible, so to speak, to subdivide the above-mentioned portion of material into two sub-portions of material, that are disposed on either side of the orifice. As a result, when the above-mentioned portion of the base is subjected to twisting while the cap is being turned over, each of the sub-portions deforms in a manner that is particularly flexible, thereby limiting the appearance of local excess stresses.

In addition, this through orifice may be arranged in accordance with the teaching of WO-A-03/059770, i.e. this through orifice forms a passage for inserting a tamperproofing tongue into a storage space defined between the base and the neck, the tamperproofing tongue associating the base with the cap away from the hinge, being connected to said base and to said cap via breakable means that are adapted to break so as to enable the tongue to be removed on first use of the stopper in order to open the cap.

The invention can be better understood on reading the following description, given purely by way of example and made with reference to the drawings, in which:

FIG. 1 is a perspective view of a stopper in accordance with the invention;

FIG. 2 is an elevation view looking along arrow II of FIG. 1;

FIG. 3 is a longitudinal section view of the neck of a container closed by the stopper of FIGS. 1 and 2;

FIG. 4 is a view analogous to FIG. 3, showing a cap of the stopper in an open position relative to a base of the stopper;

FIG. 5 is a perspective view of the stopper of FIGS. 1 and 2, showing the cap being turned over while in the open position; and

FIGS. 6 to 9 are views analogous to FIG. 2 showing respective embodiments variants of the stopper in accordance with the invention.

In FIGS. 1 to 5, a stopper 1 is shown either on its own or else mounted on the neck 2 of a container 3, such as a bottle, which is shown in part only. For convenience, the description below is oriented on the assumption that the terms “top” and “bottom”, and analogous terms, are defined with reference to a stopper placed flat on a surface that is generally horizontal in the position of FIGS. 1, 2, and 5, which amounts to assuming that the stopper is mounted on the neck 2 when the neck extends vertically lengthwise in an upward direction from the remainder of the container 3, in the configuration shown in FIGS. 3 and 4. As a result, the top side of the device 1 faces upwards in the figures, whereas its bottom side faces downwards.

The stopper 1 is made as a one-piece plastics molding and comprises a bottom base 10 of tubular shape on a circular base about a central longitudinal axis X-X. The base 10 is provided with internal ribs 11 that are situated at the same longitudinal level of the base, and that are distributed around the periphery of the base, as can be seen in FIG. 5. As shown in FIGS. 3 and 4, these ribs 11 are adapted to co-operate with an outer annular rim 4 on the neck 2 so as to prevent the base from moving around the neck.

The stopper 1 also has a top cap 20 that is hinged to the top end 10A of the base 10 in a small peripheral zone of the base, corresponding in practice to the rear portion of the stopper 1. For this purpose, the corresponding rear hinge, referenced 30, between the base and the cap comprises two flexible strips 31 connecting the top end 10A of the base directly to the bottom end 21A of a main tubular wall 21 of the cap, being formed integrally with said ends. The strips 31 form respective hinges that, by deforming, enable the cap 20 to be tilted between a closed position, as shown in FIGS. 1 to 3, in which the cap closes the neck 2, and an open position, shown in FIG. 4, in which the liquid contained in the container 3 can be poured out freely from the container through the neck 2 without being retained by the cap. The strips 31 thus define an axis A-A about which the cap tilts between its closed and open positions, it being understood that in practice, and given the way the strips deform flexibly, the position of this axis A-A is not absolutely stationary relative to the base 10, but that throughout the tilting movement of the stopper, this axis is defined instantaneously on the rear side of the stopper 1, extending in a direction that is circumferential relative to the axis X-X.

Advantageously, the strips 31 are of smaller thickness than the ends 10A and 21A of the base and of the cap, making them easier to deform.

In order to make it easier for a user to cause the cap 20 to tilt, the front peripheral portion of the cap is provided with a tab 22 that projects forwards from the main wall 21. When the user seeks to open the stopper 1, it is then possible to direct an upwardly-directed force F₁ against the bottom face of the tabs 22, as shown in FIG. 3.

In the embodiment shown in FIGS. 1 to 5, the stopper 1 advantageously presents arrangements in accordance with the teaching of WO-A-03/006333, to which the reader may refer for more details and corresponding variant embodiments. According to that teaching, the cap 20 is provided, opposite from the tab 22, i.e. in its rear peripheral portion, with a tab 23 that projects rearwards from the main wall 21, while the base 10 includes, in its rear peripheral portion, a tongue 12 integrally molded with the base and projecting upwards from the top end 10A. Going around the periphery of the base, this tongue 12 is located between the two hinge strips 31. While the cap is tilting about the axis X-X, the tab 23 comes to bear on the outside against the tongue 12 under the effect of an elastic force exerted by the strips 31. As a result of this force, the tongue 12 is pressed against the outside surface of the neck 2, said surface then exerting a reaction force on the tab 23 such that this force, in combination with the elastic force exerted by the strips 31, serves to hold the cap in its open position, as shown in FIG. 4. Advantageously, the cap 20 is then held at an opening angle of more than 180°, such that access to the neck is clearly disengaged.

The stopper 1 also has a tamperproofing tongue 40 that, prior to the first opening of the cap, associates the base 10 and the cap 20 around the major fraction of the periphery of the stopper 1, with the exception of the rear peripheral portion of the base where there are formed the hinge 30 and a crenellation 41 formed integrally with the base and projecting upwards from the top end 10A. This tongue 40 thus forms a connection of peripheral material between the base and the cap during molding of the stopper. Breakable means, designed to be broken when the tongue is withdrawn, connects said tongue to the top end 10A of the base and to the bottom end 21A of the cap, in particular in the form of respective tearable lines 42 and 43 extending continuously around the periphery of the stopper. So long as these lines 42 and 43 have not been torn, the tongue 40 prevents the cap 20 from being tilted away from its closed position. When the user desires to open the stopper for the first time, it is necessary to grasp the longitudinal end of the tongue, which is advantageously formed as a grip tab 44, and remove the tongue completely by tearing the lines 42 and 43, thereby releasing the cap, which can then be tilted into the open position. When the cap is subsequently tilted back into the closed position, its bottom end 21A comes into abutment against the crenellation 41 to stop its tilting movement.

In the embodiment shown in the figures, the stopper 1 advantageously presents arrangements in accordance with the teaching of WO-A-03/059770, to which the reader may refer for details and corresponding embodiment variants. According to that teaching, an orifice 13 is formed through the wall of the base 10 in its rear peripheral portion, at a longitudinal level that is substantially halfway up the base. This orifice 30 forms a passage for the tongue 40 once the lines 42 and 43 have been completely torn, in the sense that the tongue can be inserted through the orifice 13 into a storage space 45 defined radially between the outside face of the neck 2 and the inside face of the base 10, as shown in FIG. 4.

In order to limit the risk that the cap 20 in the open position can be torn completely away from the base 10, in particular when said cap is stressed other than to perform its normal tilting movement about the axis X-X, e.g. by a child playing with the cap 1, the base 10 is provided with two lines of weakness 14 situated in the rear peripheral portion of the base. The two lines 14 are symmetrical to each other about a diametral longitudinal plane of the base corresponding to the section plane of FIGS. 3 and 4, it being observed that for the two hinge strips 31, this plane corresponds to a plane of mutual symmetry, and also serves as a plane of symmetry both for the tongue 12 and for the orifice 13. Each line of weakness 14 includes a slot 15 that passes radially through the wall of the base 10 and that extends generally in a longitudinal direction of said base from its top end 10A towards its bottom end 10B. In the example shown in FIGS. 1 to 5, the slots 15 extend lengthwise in respective directions that are not accurately parallel to the axis X-X, but that are slightly curved in projection onto a diametral plane perpendicular to the plane of symmetry of the lines 14, having their concave sides facing towards the hinge 30, with the straight line interconnecting their opposite ends 14A and 14B forming an angle α with the axis X-X (FIG. 2), which angle faces upwards and has a value of less than 45°. Thus, as can clearly be seen in FIG. 2, the two slots 15 converge towards each other on going away from the top end 10A of the base, each presenting a longitudinal outline that is slightly curved, with its concave side generally centered on the hinge 30.

The respective top ends 14A of the lines of weakness 14, corresponding respectively to the top ends of the corresponding slots 15, open out into the top 10A of the base 10 and are situated on either side of the hinge 30, i.e. on the outside of the respective side edges of the strips 31 that are furthest apart from each other. In the examples shown in the figures, each line of weakness 14 opens out at its top end 14A into a gap between the corresponding strip 31 and either the tamperproofing tongue 40 or the crenellation 41.

Each line of weakness 14 also includes a breakable bridge 17 connecting together the two longitudinal edges of the corresponding slot 15 at the top end 14A of the line of weakness. The bridges 17 are configured and dimensioned so that the presence of the lines of weakness 14 does not disturb the dynamic behavior of the hinge 30 when the cap 20 is tilted about the axis A-A between its open and closed positions. In contrast, when the cap 20 in the open position is twisted to rotate about an axis B-B that is simultaneously substantially perpendicular to the axis A-A and that extends in a diametral plane of the cap 20, as represented by arrow F₂ in FIG. 5, the bridges 17 are configured and shaped so as to break almost immediately, i.e. so as to break before the strips 31 of the hinge 30 are subjected to stresses that would tear through the strips. As a result, once the bridges 17 have broken, the portion of material 10 _(14/14) of the base 10 that lies between the two lines of weakness 14 around the periphery of the base and that carries the hinge 30, is no longer connected to the remainder of the base over the entire longitudinal dimension l₁₅ of the slots 15. This portion of material 10 _(14/14) can then be subjected to twisting about the axis B-B over the entire length l₁₅ of the slots 15, in particular until the cap 20 has been turned right over by turning F₂ through 180° about the axis B-B, as shown in FIG. 5.

Since the stresses associated with twisting the portion of material 10 _(14/14) are distributed over the entire length l₁₅ of the slots 15, the intensity of the stress on the strips 31 remains moderate, and in practice is not sufficient to tear through them, and consequently tear the cap 20 away from the base 10. For this purpose, and with practical dimensioning, the length l₁₅ is not less than one-fourth, and is preferably half the length of the total length L of the base measured between its top and bottom ends 10A and 10B.

In practice, the presence of the through orifice 13 subdivides the portion of material 10 _(14/14) into two individual sub-portions 10 _(14/13) and 10 _(13/14) on either side of the orifice around the peripheral direction of the base, such that each of these sub-portions is worked individually in twisting, thereby limiting potential excess stress, particularly in the middle peripheral zone of the portion 10 _(14/14). When the stopper 1 reaches the configuration of FIG. 5, these sub-portions 10 _(14/13) and 10 _(13/14) cross each other.

In addition, insofar as the two lines of weakness 14 converge towards each other at their bottom ends 14B, it will be understood that the most intense twisting stresses to which the portion of material 10 _(14/14) is subjected are applied to the portion 10 _(14B/14B) that extends between the bottom end 14B around the periphery of the base, as represented by a horizontal shaded region in FIG. 2. In the embodiment of FIGS. 1 to 5, this portion 10 _(14B/14B) is interrupted in its middle by the orifice 13. Thus, the dimensioning of this portion 10 _(14B/14B) is critical in the sense that it must conserve its structural integrity during twisting about the axis B-B. In particular, in comparison with the strips 31, that are designed to conserve their structural integrity while being subjected to a level of stress intensity that is minimized given the downward convergence of the lines of weakness 14, this portion 10 _(14B/14B) advantageously presents a total section of material in a plane perpendicular to the axis X-X that is less than or equal to the section of the strips 31 and/or a thickness that is strictly greater than the thickness of the strips.

Advantageously, in addition to conserving the structural integrity of the hinge 30 when the cap 20 is turned over about the axis B-B, the lines of weakness 14 are designed to limit any risk of the portion 10 _(14/14) being torn away when the cap 20, after being turned over, and being pulled away from the base 10 along the axis B-B, as represented by arrow F₃ in FIG. 5. With reference to the stopper 1 in its FIG. 5 configuration, if traction is applied to the cap 20 along arrow F₃, the low portion of the base 10 withstands the corresponding traction stresses longitudinally in line with the slots 15. In order to guarantee a high level of traction strength, each slot 15 is extended by an elongate opening 18 that is formed in the base and that extends lengthwise from the bottom end 14B of the corresponding line of weakness 14 in a direction that is substantially peripheral relative to the base and away from the other line of weakness 14. As a result, when traction F₃ is applied to the cap, the tears and cracks in the plastics material constituting the base 10 do not propagate longitudinally to extend the slots 15 directly, but are deflected by the openings 18 in a peripheral direction relative to the base 10, axially between the level of the ends 14B of the lines of weakness 14 and the bottom end 10B of the base. In practice, and as clearly visible in FIG. 2, the openings 18 extend lengthwise in respective directions that are not accurately circumferential relative to the axis X-X but that, in projecting on a diametral plane perpendicular to the plane of symmetry of the lines of weakness 14, form respective downwardly-facing angles β relative to said axis, the angle β having a value lying in the range 45° to 90°.

Thus, the stopper 1 satisfies, amongst others, the requirements of French standard NF EN 71-1 or S 51-212 relating to child safety, in the sense that its cap 20 can be turned over, in particular through 180°, and can be pulled away from the base 10 under predetermined conditions laid down by the standard, without the material connection between the cap and the base being completely broken, in particular at the hinge strips 31 of the hinge 30, even though these are portions of the stopper 1 that are fragile because of their small relative thickness.

FIGS. 6 to 9 respectively show four variants of the stopper 1. Below, only the differences between each of these variants and the embodiment of FIGS. 1 to 5 are described in detail.

The stopper of the FIG. 6 variant does not have elongate openings 18. This disposition makes the stopper easier to fabricate. In order to guarantee that the portion of material 10 _(14/14) has sufficient traction strength, the respective bottom ends 14B of the lines of weakness 14 are provided far enough away from the bottom end 10B of the base 10 to ensure that the two longitudinal portions of material 14 _(14B/10B) extending between the bottom end 14B of each line of weakness 14 and the bottom end 10B of the base, and represented by two vertical shaded regions in FIG. 6, withstand high levels of traction stress without breaking. For this purpose, the longitudinal dimension l_(14B/10B) of these portions 10 _(14B/10B) is not less than 10% of the length L of the base.

Naturally, this longitudinal dimensioning of the portions 10 _(14B/10B) may be provided in the embodiment of FIGS. 1 to 5, thus advantageously being combined with the presence of the two openings 18.

In FIG. 7, there can be seen a variant of the stopper 1 that associates one of the lines of weakness 14, specifically the lines shown in the left-hand portion of the figure, with the presence of one of the elongate openings 18, while the other line of weakness 14, i.e. the line shown on the right, is not associated with such an opening, while nevertheless dimensioning the length l_(14B/10B) as shown in FIG. 6. In this way, the behavior of the portion 10 _(14/14) remains substantially uniform on either side of the orifice 13, the sub-portions 10 _(14/13) and 10 _(13/14) being symmetrical to each other when the cap 20 is subjected to twisting F₂ about the axis B-B. In contrast, when it is subjected to traction F₃ along the axis B-B, the low portion of the base 10 between the ends 14B of the two lines of weakness 14 and the end 10B of the base behave asymmetrically on either side of the plane of symmetry of the lines 14: on the side provided with the opening 18, tears and cracks in the plastics material are guided in a direction that is substantially peripheral relative to the base, as described in greater detail above with reference to FIG. 2, whereas on the side that does not have an opening such as the opening 18, the tears and cracks in the plastics material propagate directly to extend the corresponding line of weakness 14 longitudinally, essentially within the corresponding longitudinal portion 10 _(14B/10B), as represented by a vertical shaded region in FIG. 7.

In comparison, for traction of given intensity F₃, the tears in the low portion of the base 10 are more marked and come closer to the end 10B of the side of the base shown in the right-hand portion of FIG. 7 than to the side shown in the left-hand portion. In the limit, if the traction intensity is great enough, the base 10 breaks in the portion 10 _(14B/10B) that does not have the opening 18, but it does not break in line with the opening 18, such that the stopper 1 together with its base as broken in this way over its entire length L remains as a single piece, in particular with its cap 20 securely connected to the base, it being observed that this piece may be of dimensions such that it is practically impossible for a child to inhale it.

The variant stopper 1 shown in FIG. 8 does not have the through orifice 13, thus preventing the tongue 40 being stowed between the neck 2 and the base 10 after the tongue has been torn off, but enabling the portion of material 10 _(14B/14B) to be of a continuous shape without any interruption at an orifice 13.

The variant stopper 1 shown in FIG. 9 differs from the embodiment of FIGS. 1 to 5 by the facts that firstly the hinge 30 has only one hinge strip 31, and secondly the two lines of weakness 14 that extend from the top end 10A of the base 10 on either side of the hinge 30 are accurately parallel to the axis X-X.

It is also possible to envisage rearranging and varying the stopper 1 and its variants as described above. For example, elongate shapes other than the lines 14 may be provided for the zones of weakness provided in the base 10 so as to allow the cap 20 to be turned over without tearing through the hinge 30. In addition, the slots 15 of the lines of weakness 14 do not need to be curved as shown in FIGS. 1 to 8 in order to be effective: they may be curved in the opposite direction relative to that shown in the figures, or as shown in FIG. 9, these slots may equally well be rectilinear, or the slots may include successive segments that are rectilinear and/or curved, and it is possible for them to have curvature that is positive or negative. Similarly, a plurality of breakable bridges such as the bridge 17 may be formed in the zones of weakness, in particular depending on the precise shape of these zones. 

1-11. (canceled)
 12. A stopper of plastics material for a neck of a container, the stopper comprising a generally tubular base for surrounding the neck and a closure cap that is formed in a peripheral portion of the base integrally with a first longitudinal end of the base, forming a hinge with one or more hinge members defining a tilt axis for tilting the cap relative to the base between open and closed service positions, wherein the base presents two elongate zones of weakness that extend lengthwise from the first end of the base towards the second longitudinal end thereof, being situated at said first end on either side of the hinge, and that are adapted to break before the hinge can be torn through when the cap, in the open position, is turned over around a twist axis extending transversely to the tilt axis.
 13. A stopper according to claim 1, wherein the two zones of weakness are dimensioned and configured relative to the base in such a manner that, after breaking, they define between them a material portion of the base, that carries the hinge and that is adapted to work in twisting without breaking when the cap is turned over about the twist axis through at least 180°.
 14. A stopper according to claim 12, wherein each zone of weakness presents, in the longitudinal direction of the base, a dimension that is greater than one-fourth the length of the base.
 15. A stopper according to claim 14, wherein said dimension is greater than half length of the base.
 16. A stopper according to claim 12, wherein the two zones of weakness extend lengthwise converging towards each other on going away from the first end of the base.
 17. A stopper according to claim 16, wherein the two zones of weakness define, between their ends remote form the first end of the base and in the peripheral portion of the base associated with the hinge, a material portion of base, that presents, in a plane perpendicular to the longitudinal direction of the base, a section that is greater than or equal to that of the hinge member(s) of the hinge.
 18. A stopper according to claim 16, wherein the two zones of weakness define, between their ends remote from the first end of the base and in the peripheral portion of the base associated with the hinge, a material portion of the base, that presents a thickness that is strictly greater than the thickness of the hinge member(s) of the hinge.
 19. A stopper according to claim 12, wherein a longitudinal material portion of the base, that extends between the longitudinal end of at least one of the zones of weakness opposite from the first end of the base, and the second end of the base, presents, in the longitudinal direction of the base, a dimension that is greater than 10% of the length of the base.
 20. A stopper according to claim 12, wherein at least one of the zones of weakness is extended at its longitudinal end remote from the first end of the base by an elongate opening formed in the base, said opening extending lengthwise from said zone of weakness in a direction that is substantially peripheral relative to the base and away from the other zone of weakness.
 21. A stopper according to claim 12, wherein each zone of weakness comprises firstly a through slot that extends lengthwise from the first end towards the second end of the base, and secondly at least one breakable element connecting together the longitudinal sides of the slot, and adapted to break before the hinge can be torn through when the cap in its open position is turned over about the twist axis.
 22. A stopper according to claim 21, wherein the at least one breakable element is disposed at the longitudinal end of the slot that is situated at the first end of the base.
 23. A stopper according to claim 12, wherein the two zones of weakness define between them a material portion of the base, that carries the hinge and that is provided, in its middle portion around the periphery of the base, with a through orifice of elongate shape in the longitudinal direction of the base. 